Although he stepped down from BusinessNZ last year, O'Reilly still serves as chair of the Business and Industry Advisory committee to the OECD.
The first New Zealander to lead the organisation, O'Reilly said the group was a bit like BusinessNZ but on a bigger scale.
"It's a lot of fun to be here, but you're also not allowed to make a mistake, right?" O'Reilly said from Paris, where he was attending an OECD meeting.
"You're representing the OECD member states, so it's a challenge to do it well."
As well as the committee, O'Reilly is also a member of the governing body of the International Labour Organisation in Geneva.
He has also recently set up Iron Duke Partners, a Wellington-based public policy advisory firm.
O'Reilly said the honour was a "vote of confidence in business organisations".
In his time with BusinessNZ, O'Reilly said he tried to shift the thinking towards how the sector interacts with the community.
"What struck me is the business voice was often quite centered on business - and that's quite appropriate, it's not a criticism - but I felt we needed to centre it on communities and centre it on the wider success of New Zealand," he said.
"In my view business was and is a means to an end. The end that you seek is a successful community and a successful society and prosperity for the country."